1. Field of the invention
The present invention relates to a boat control system having a boat propulsion system and a remote control device for transmitting an operation signal to the boat propulsion system, and further relates to a boat provided with the boat control system.
2. Description of the Related Art
A conventional technique in this field is disclosed in JP-A-04-38297.
According to JP-A-04-38297, an outboard motor including an internal combustion engine, a propeller for propulsion, and so forth is provided on the outside of the boat main body; a steering motor for horizontally rotating the outboard motor is provided on a connecting portion between the boat main body and the outboard motor; and a steering motor and a steering wheel as a boat propulsion unit operation device provided near an operator's seat are connected by a communication line via which signals can be sent and received.
According to JP-A-04-38297, it is disclosed that the communication line for performing communication between a pair of nodes is duplicated so that communication is normally performed by one communication line if the other communication line is broken. This may increase the resistance to a communication failure.
A technique in which communication lines of a boat are duplicated is illustrated in FIG. 6. In the drawing, an engine side electric control unit (ECU) for controlling an engine of an outboard motor is provided in the outboard motor as an example of a boat propulsion system, and a remote control side ECU is provided in a remote control device which transmits an operation signal to the boat propulsion system.
The engine side ECU and the remote control side ECU define duplicated communication paths in which a pair of nodes is connected by a pair of communication lines to secure appropriate communication. Consequently, even when one communication line is broken, communication is normally performed via the other communication line to provide engine control.
Moreover, to further secure safety, a warning is given to an operator by lighting a lamp or by some other method if one communication line is broken. If the two communication lines are broken, the engine is stopped (fail control) to control the generation of the propulsive force.
In other words, the engine side ECU and the remote control side ECU detect a wire break in the network. A system is started (a main switch is turned on) as shown in FIG. 7(a). After this, as shown in FIG. 7(b), one communication line (CAN Ch1) is turned from a “Normal” status to a “Wire break” status. After a time-out determination time passes, Ch1 error information is changed from “None” indicating that a target communication line is in a status in which no abnormality is found, to “Issued” indicating that the target communication line is causing an abnormality and is in a status in which communication is impossible. Consequently, a system mode is turned from a “Normal” mode indicating that the both of the duplicated communication paths are normal to a “Warning” mode indicating that one of the duplicated communication paths is in a status in which there is an abnormality. As a result, an operator is informed of the fact that a wire break occurs in one of the duplicated communication paths by lighting a warning lamp or by some other method.
After one of the duplicated communication paths is broken in the network, the other communication line (CAN Ch2) may be turned from the “Normal” mode to the “Wire break” mode. In this case, as shown in FIG. 7(c), after the time-out determination time passes, Ch2 error information is changed from “None” to “Issued.” Consequently, a system status is turned from the “Warning” status to an operation mode at the time when both of the duplicated communication paths cannot perform communication, that is, a “Fail” mode as an operation mode for securing appropriate navigation of the boat. As a result, fail control is performed as a control for securing appropriate running of the boat, and thereby a throttle is set to a fully closed status.
However, according to the network assumed on the basis of the invention described in JP-A-04-38297, a wire break in relation to the engine side ECU and a wire break in relation to the remote control side ECU are both detected on the basis of a change in a communication status after the system is started (a change in continuity of an electrical signal, a change in a status of data transfer, and the like). Therefore, a problem illustrated in FIGS. 8(a)-8(c) may occur.
As shown in FIG. 8(a) and FIG. 8(b), assume that one communication line (CAN Ch1) in the duplicated communication paths is already broken before the system is started (before the main switch is turned on) in the assumed network. In this case, the one communication line does not cause a change in a communication status after the system is started (after the main switch is turned on). Therefore, the wire break is not detected, and, accordingly, the Ch1 error information remains “None.” As a result, the “Warning” mode is not set, and the operator does not recognize that the one communication line is broken.
Further, assuming that after the system is started, another communication line (CAN Ch2) in the duplicated communication paths in which the one communication line has been already broken may be turned from the “Normal” mode to the “Wire break” mode in the assumed network. In this case, after the time-out determination time passes, Ch2 error information is changed from “None” to “Issued.” Accordingly, each ECU determines that a first communication line is broken. As a result, as shown in FIG. 8(c), the “Normal” mode is turned to the “Warning” mode, and nothing other than lighting the warning lamp or the like may be performed.
On the other hand, it may be considered that the wire break is detected on the basis of a communication status between the engine side ECU and the remote control side ECU at a time of a system start in the assumed network. In this case, it may be necessary to change settings of the remote control side ECU depending on whether one remote control side ECU or a plurality of remote control side ECUs is provided on one hull. Specifically, in the former case, since the remote control side ECU communicates with the engine side ECU as the only node, it is only necessary to determine a communication status with the engine side ECU at a time of a system start. On the other hand, in the latter case, it is necessary for at least one remote control side ECU to determine a communication status of a plurality of nodes (another remote control side ECU and the engine side ECU, for example) at a time of a system start. Consequently, it is necessary to change the arrangement depending on whether one remote control side ECU is provided or a plurality of remote control side ECUs is provided on one hull. Therefore, it is difficult to commonly use one ECU as a remote control side ECU in a case in which one remote control side ECU is provided on one hull and also as an ECU in a case in which a plurality of remote control side ECUs is provided on one hull. This causes a problem in which manufacturing processes and the cost in commercialization are increased.